Field of the Invention
The invention relates to a sensing system and a sensor chip, and more particularly to a sensing system including a sensor chip with a microelectrode array.
Background Information
Due to the longer lifespan, physical examinations have become increasingly important in respect of disease screening, medical diagnosis or geriatric care. In conventional analysis, a to-be-inspected portion of a specimen is separated using a centrifuge. After adding some reagents, a condition of the specimen may be determined according to a presented color or a concentration of a product. Such a conventional method requires more manpower and time for analysis, resulting in a relatively high cost.
On the other hand, biochips contribute to fast and effective analysis, and are suitable for use at home, achieving both reduction of personnel cost and increasing popularity. An LOC (laboratory-on-a-chip), also called a μTAS (micro total analytical system), microminiaturizes and integrates on a chip operations in a lab, resulting in reduced overall reaction time, promoted efficiency, and significant reduction in inspection errors. Such integration of medical analysis and electronic system saves time, space and human resource, thereby greatly reducing cost, and being a potentially important product in the future.
Most conventional LOCs use a glass substrate to build thereon, a set of micro flow paths and valve components that control the micro flow paths, based on MEMS (micro-electro-mechanical system) techniques and a semiconductor fabrication process, and cooperate with external pump devices and inspection devices to form a platform for completely processing and analyzing specimens. Separation and purification of the specimen, mixing of the specimen and the reagents, and judgment of the result may be provided using such a platform.
However, the LOC with the micro flow paths and the valve components may encounter the following issues:
1. Due to difficulty in heterogenous integration, control components and inspection components for the LOC must be setup externally. In general, a large number of the external control components lead to a large number of input/output (I/O) signal lines, resulting in limitations on usable area of the LOC.
2. Most LOCs cooperate with an external pump to enable flow of a droplet in the micro flow paths from a position with a relatively high pressure to a position with a relatively low pressure. However, since the micro flow paths are in a sealed space, the pressure generated by the pump may cause the droplet to flow arbitrarily, leading to ineffective driving of the droplet, waste of the specimen, and low sensitivity in analysis.
3. Since a layout of the micro flow paths of the conventional LOC is fixed, the LOCs with different layouts of the micro flow paths may be required for different analysis. Personnel may need to learn operations for the LOCs with different layouts of the micro flow paths, leading to higher costs in training personnel and product development.
4. Although many methods have been proposed to control fluid in the micro flow paths, the applicant is not aware of a conventional method that additionally provides a mechanism enabling readout of a type of the fluid, which may reduce errors in experiments.